Organic smoke suppressant additive and distillate hydrocarbon fuel compositions containing same

ABSTRACT

ORGANIC SMOKE SUPPRESSANT ADDITIVE AND DISTILLATE HYDROCARBON FUEL COMPOSITIONS CONTAINING SAID ADDITIVE. THE ADDITIVE COMPRISES AN ETHER OF HYDROQUINONE AND A MIXTURE OF ISOPROPYL ALCOHOL AND DIACTONE ALCOHOL. THE PREFERRED DISTILLATE HYDROCARBON FUEL COMPOSITION COMPRISES A MAJOR PROPORTION OF DIESEL FUEL AND A MINOR PROPORTION OF THE ADDITIVE.

United States Patent Office 3,817,720 Patented June 18, 1974 ABSTRACT OF THE DISCLOSURE Organic smoke suppressant additive and distillate hydrocarbon fuel compositions containing said additive. The additive comprises an ether of hydroquinone and a mixture of isopropyl alcohol and diacetone alcohol. The preferred distillate hydrocarbon fuel composition comprises a major proportion of diesel fuel and a minor proportion of the additive.

BACKGROUND OF THE INVENTION The petroleum industry has encountered problems in supplying middle distillate and heavy residual oils suitable for use in compression ignition and jet engines and which will not contribute materially to the pollution of the atmosphere through soot and smoke production. Attempts have been made to reduce the soot and smoke formed during the combustion of liquid hydrocarbon fuels. For example, smoke suppressant additives derived from certain metal salts have been employed in distillate hydrocarbon fuels such as diesel fuels, but they are often characterized by a number of deficiencies. Typical shortcomings of prior art metal-containing smoke suppressant additives are thermal instability, poor water tolerance, poor oxidative stability, a tendency toward gel formation, the formation of crankcase deposits as a result of blowby from engine cylinders, and clogging of fuel injectors. In addition, products of combustion of fuels having metal-containing smoke suppressant additives include ecologically harmful metal compounds such as metal oxides and sulfates.

Accordingly, there exists a need for distillate hydrocarbon fuel compositions having reduced soot and smoke forming properties and which are, in addition, free of the undesirable side effects and deficiencies of prior art distillate hydrocarbon fuel compositions.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide distillate hydrocarbon fuel compositions having reduced smoke and soot forming characteristics.

It is another object of this invention to provide distillate hydrocarbon fuel compositions having reduced soot and smoke forming characteristics and which do not form metal compounds as products of combustion.

Still another object of this invention is to prepare a completely organic smoke suppressant additive for use in distillate hydrocarbon fuels.

Yet other objects and advantages will be apparent to those skilled in the art from the following description.

The foregoing objects are achieved in accordance with the practice of this invention. Broadly, this invention consists of a smoke suppressant additive for distillate hydrocarbon fuels comprising an ether of hydroquinone and a mixture of isopropyl alcohol and diacetone alcohol; and distillate hydrocarbon fuel compositions having reduced smoke and soot forming characteristics comprising a major proportion of a distillate hydrocarbon fuel and a minor proportion of the smoke suppressant additive of the invention.

Thus, by the practice of this invention there are provided completely organic smoke suppressant additives and distillate hydrocarbon fuel compositions containing said additives which have reduced soot and smoke forming properties and which in addition overcome a number of the deficiencies of prior art metal-containing distillate hydrocarbon fuel compositions. Accordingly, the distillate hydrocarbon fuel compositions of this invention do not have a tendency toward gel formation, do not form crankcase deposits as a result of blowby from cylinders, do not clog fuel injectors, and do not form metal compounds as products of combustion.

DETAILED DESCRIPTION The smoke suppressant additive of this invention comprises an ether of hydroquinone and a mixture of isopropyl alcohol and diacetone alcohol. The ether of hydroquinone may be either a monoether or a diether of hydroquinone having a structural formula selected from wherein R and R are preferably hydrocarbyl groups but they may be organyl groups containing hetero atoms, and wherein n is an integer from 1 to about 10 and preferably from 1 to about 6. R and R each broadly contains 1 to about 25 carbons and preferably 1 to about 20 carbons. R and R may be aliphatic, aromatic, naphthenic or may contain segments of aliphatic, aromatic, or naphthenic character in the same group. Aliphatic and naphthenic groups or segments may be either saturated or unsaturated. The preferred hetero atom that may be present in R or R is oxygen. R and R may be either the same or different in the case of diethers of hydroquinone. Examples of suitable R and R groups are methyl, ethyl, t-butyl, cyclohexyl, ethylcyclohexyl, cyclohexenyl, benzyl, phenethyl, tolyl, xylyl, cyclododecyl,

and

CHz(CHz)a C -O-C2H and CHa(CH2)1a( )-O-CzH4-: The preferred ether of hydroquinone has the structure t- -Q- i wherein R is cyclododecyl, n is 6, and the points of attachment of the hydroquinone groups are the 1, 2, 5, 6, 9 and 10 positions of the cyclododecane ring.

As set forth above, the smoke suppressant additive of this invention contains, in addition to the ether of hydroquinone, a mixture of isopropyl alcohol and diacetone alcohol. The volume ratio of isopropyl alcohol to diacetone alcohol is broadly from about 1:3 to about 3:1. The preferred volume ratio is about 1:1.

The weight ratio of the ether of hydroquinone to the mixture of isopropyl alcohol and diacetone alcohol in the instant smoke suppressant additive is broadly from about 1:10 to about 10:1 and preferably from about 1:3 to about 3:1. The most preferred smoke suppressant additive of this invention comprises 3 parts by weight of the ether of hydroquinone having the structure a- Q-e.

wherein R is cyclododecyl and 4 parts by weight of a mixture of isopropyl alcohol and diacetone alcohol having a volume ratio of 1:1.

The distillate hydrocarbon fuel compositions of this invention broadly comprise a major proportion of .a distillate hydrocarbon fuel and a minor proportion of the smoke suppressant additive. In practice, particularly useful are distillate hydrocarbon fuel compositions comprising a major proportion of a distillate hydrocarbon fuel and about 0.2-2.0 weight percent, and preferably about 0.4-1.2 weight percent, of the smoke suppressant additive of the instant invention. Most preferred are fuel compositions comprising a major proportion of a distillate hydrocarbon fuel and about 0.7 weight percent of the smoke suppressant additive comprising 3 parts by weight of the ether of hydroquinone having the structure RHQOH].

' wherein R is cyclododecyl and 4 parts by weight of a mixture of isopropyl alcohol and diacetone alcohol having a volume ratio of 1: 1. The distillate hydrocarbon fuel may, for example, be jet fuel, a No. 2 burner fuel, or a diesel fuel. This invention, however, is particularly applicable to diesel fuels.

The effectiveness of the smoke suppressant additives of the invention was determined by comparing the percent of smoke reduction of a diesel fuel to which had been added said smoke suppressant additive relative to the percent of smoke reduction of a diesel fuel to which had been added a commercial metal-containing smoke suppressant additive. The percent effectiveness of a smoke suppressant additive of this invention relative to the commercial smoke suppressant additive may therefore be represented by the expression:

Percent Eflectiveness wherein the numerator refers to the percent smoke reduction of diesel fuel containing a smoke suppressant additive of the invention and the denominator refers to the percent smoke reduction of diesel fuel containing the commercial metal-containing additive. Thus, a percent effectiveness greater than indicates a positive smoke reduction by the smoke suppressant additive of the invention. The greater the percent effectiveness, the closer the additive of the invention as a smoke suppressor is to the commercial smoke suppressant additives. The commercial smoke suppressant additive used as a reference was a mixture of barium alkylphenates and carbonated barium alkylphenates. The reference diesel fuel composition contained 0.35 weight percent of the barium-containing commercial smoke suppressant additive.

The smoke suppressant additives of this invention are evaluated by being incorporated in a diesel fuel and the resultant diesel fuel composition used to power a 4-cylinder John Deere tractor engine equipped with a Hartridge Smoke Meter. The engine is first warmed up on the base diesel fuel containing no smoke suppressant additive under conditions wherein no visible black smoke is observed in the exhaust gas. The fuel flow is then increased until the appearance of visible black smoke in the exhaust gas corresponding to a Hartridge Smoke Number (HSN) of about 65. The diesel fuel composition containing the smoke suppressant additive of the invention is then substituted for the base fuel and the engine run for about five minutes to allow stabilization. The Hartridge Smoke Number is then determined. The cycle of base fuel and inventive fuel composition is repeated twice more. The Hartridge Smoke Numbers of the base fuel are averaged as are those of the inventive fuel composition. Using the averaged smoke numbers, the percent smoke reduction of the fuel composition containing the smoke suppressant additive of the invention relative to the base fuel is determined.

The above procedure is repeated using base diesel fuel and a diesel fuel composition containing 0.35 weight 4 percent of the barium-containing commercial smoke suppressant adidtive. The percent effectiveness of the smoke suppressant additive of the invention relative to the commercial additive is determined by means of the foregoing expression.

The instant invention will be further illustrated by the following specific examples.

EXAMPLE I Diesel fuel compositions are prepared containing smoke suppressant additives of the invention in which the ether of hydroquinone has the structural formula wherein R and R are the same in each molecule and n is l. The mixture of isopropyl alcohol and diacetone alcohole component of the additives has a 1:1 volume ratio. The foregoing diesel fuel composition, and a base diesel fuel containing no smoke suppressant additive, are used in the John Deere tractor engine and the Hartridge Smoke Numbers determined. From the Hartridge Smoke Numbers, the percent smoke reductions of the diesel fuel compositions containing the smoke suppressant additives of the invention relative to the base diesel fuel are determined. A diesel fuel composition containing 0.35 weight percent of the commercial smoke suppressant additive comprising a mixture of barium alkylphenates and carbonated barium alkylphenates is also used to fuel the John Deere tractor engine, and from the Hartridge Smoke Numbers, the percent smoke reduction relative to the base diesel fuel is determined. The percents effectiveness of the fuel compositions containing the smoke suppressant additives of the invention relative to the fuel composition containing 0.35 weight percent of the commercial bariumcontaining smoke suppressant additive are determined by means of the expression:

Percent Effectiveness Percent smoke reduction Percent smoke l'edllCtiO (roferenoe) The identities of the R and R groups of the hydroquinone others, the makeups of the fuel compositions, and the percents effectiveness of the smoke suppressant additives are set forth in Table I.

From the data in Table I, it is apparent that the additives of this invention comprising an ether of hydroquinone having the formula and a mixture of isopropyl alcohol and diacetone alcohol are effective smoke suppressants. Thus, distillate hydrocarbon fuel compositions containing such additives are characterized by an appreciable reduction in their smoke forming characteristics. In addition, many deficiencies of the prior art metal-containing smoke suppressant additives, particularly the formation of metal compounds as products of combustion, are overcome.

EXAMPLE 11 Example I is repeated using diesel fuel compositions containing smoke suppressant additives of this invention wherein the ether of hydroquinone has the structural formula i- -Q- l In one of the others employed, R is ethylcyclohexyl, n is 4, and the ether has the structural formula (|JHCHzO-OH In another ether of the example, R is cyclododecyl, n is 6, and the points of attachment of the hydroquinone groups are the 1, 2, 5, 6, 9 and positions of the cyclododecane ring. Also employed are simple ethers where n is 1. Each additive contains a 1:1 by volume mixture of isopropyl alcohol and diacetone alcohol. The percents effectiveness of these smoke suppressant additives of the instant invention are again determined in relation to diesel fuel compositions containing 0.35 weight percent of the commercial smoke suppressant additive comprising a mixture of barium alkylphenates and carbonated barium alkylphenates. The identities of the R groups of the hydroquinone ethers, the values of n, the makeups of the fuel compositions, and the percents effectiveness of the smoke suppressant additives are illustrated in Table II.

duced soot and smoke forming characteristics. The distillate hydrocarbon fuel compositions of this invention not only have reduced soot and smoke forming properties, but they also overcome a number of deficiencies of prior art metal-containing distillate hydrocarbon fuel compositions. Accordingly, the distillate hydrocarbon fuel compositions of this invention do not have a tendency toward gel formation, do not form crankcase deposits as a result of blowby from cylinders, do not clog fuel injectors, and, most importantly, do not form metal compounds as combustion products.

We claim:

1. A smoke suppressant additive for distillate hydrocarbon fuels comprising (a) an ether of a hydroquinone selected from the group consisting of wherein R and R are selected from the group consisting of hydrocarbyl groups containing 1 to about carbons, CH3 6COOC2H4 and CH (CH COOC H and wherein n is an integer from 1 to about 10 and (b) a mixture of isopropyl alcohol and diacetone alcohol wherein the volume ratio of isopropyl alcohol to diacetone alcohol is from about 1:3 to about 3:1 and wherein the weight ratio of said ether of a hydroquinone to said mixture of alcohols is from about 1:10 to about 10:1.

2. The smoke suppressant additive of claim 1 wherein R and R are hydrocarbyl groups, n is an integer from 1 to about 6, the volume ratio of isopropyl alcohol to diacetone alcohol is about 1:1, and the weight ratio of the ether of hydroquinone to said mixture of alcohols is from about 1:3 to about 3:1.

3. The smoke suppressant additive of claim 2 in which the ether of hydroquinone has the structure RHQM].

TABLE II Diesel fuel, Wt. percent- 99. 1 99. 5 99. 4 99. 3 99. 1 99. 4 9. 3 99. 4 1:1 by volume mixture of isopropyl alcohol plus diacetone alcohol, wt. percent 0. 4 0. 4 0. 4 0. 4 0. 4 0. 4 0. 4 0. 4 Hydroquinono ether where R is- Ethylcyclohexyl and n is 4, wt. percent 0. 5 Cyelododecyl and 11 is 6, W15. Per 0.1 0. 2 0. 3 0.5 Phenethyl and n is 1, wt. percent 0. 2 0.3 Benzyl and 'n is 1, wt. percent- 0. 2 Percent efiectiV q 22 9 26 40. 5 10 22. 5 1O 22 The data in Table H show that the additive of this invention comprising an ether of a hydroquinone having the formula and a mixture of isopropyl alcohol and diacetone alcohol, when incorporated in a distillate hydrocarbon fuel, yield distillate hydrocarbon fuel compositions having significantly reduced soot and smoke forming characteristics. The distillate hydrocarbon fuel compositions also overcome a number of the deficiencies of prior art metal-con taining smoke suppressant additives, particularly the formation of metal-containing products of combustion.

While this invention has been exemplified by the presentation of working examples employing diesel fuel as the distillate hydrocarbon fuel, it will be understood that the smoke suppressant additives of this invention function as such in distillate hydrocarbon fuels generally, e.g., diesel fuels, jet fuels, and No. 2 burner fuels. It will also be understood that, while specific smoke suppressant additives have been exemplified, this invention is not limited thereto.

Thus, this invention provides completely organic smoke suppressant additives and distillate hydrocarbon fuel compositions containing said additives which have rewherein R is cyclododecyl and the points of attachment of the hydroquinone groups are the 1, 2, 5, 6, 9 and 10 positions of the cyclododecane ring, and wherein the weight ratio of said ether of hydroquinone to said 1:1 by

volume mixture of isopropyl alcohol and diacetone alcohol is 3:4.

4. A distillate hydrocarbon fuel composition having reduced smoke and soot forming characteristics comprising a major proportion of a distillate hydrocarbon fuel and about 0.2-2.0 weight percent of the smoke suppressant additive of claim 1.

5. The distillate hydrocarbon fuel composition of claim 4 wherein said distillate hydrocarbon fuel is seelcted from the group consisting of diesel fuel, jet fuel, and No. 2 burner fuel.

6. A diesel fuel composition having reduced smoke and soot forming characteristics comprising a major proportion of diesel fuel and about 0.7 weight percent of the smoke suppressant additive of claim 3.

7. A distillate hydrocarbon fuel composition comprising a major proportion of a distillate hydrocarbon fuel selected from the group consisting of diesel fuel, jet fuel, and No. 2 burner fuel and about 0.2-2.0 weight percent of the smoke suppressant additive of claim 2.

7 8. A distillate hydrocarbon fuel composition compris- 2,662,817 ing a major proportion of a distillate hydrocarbon fuel 3,086,355 selected from the group consisting of diesel fuel, jet fuel, 3,560,173 and N0. 2 burner fuel and about 0.4-1.2 weight percent of the smoke suppressant additive of claim 2. 5 770 239 References Cited UNITED STATES PATENTS 1,423,049 7/ 1922 TUIliSOIl 44-77 2,699,385 1/1955 Stevens et a]. 44-57 10 2,646,348 7/1953 Neudeck 44-56 44-57, 77 2,110,078 3/1938 Burwell 4457 X 8 12/1953 Russell et al. 4453 4/1963 Mickel et al. 4456 X 2/ 1971 Coffey et al. 44-56 FOREIGN PATENTS 3/1957 Great Britain 445 6 PATRICK P. GARVIN, Primary Examiner A. H. METZ, Assistant Examiner US. Cl. X.R. 

